Fin command randomizes extrusion direction everytime?

Don’t mind the surface backface render fail. That’s another story for another time. :stuck_out_tongue:
All I’m doing here is RMB to repeat last command (Fin) + Click the Srf edge + Click the Srf + RMB to finish command.

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Hi Hunam - Yep, I know - it is messy. I’ll see if we can sort it out - thanks for the reminder. The problem is, I guess, that fin appears to use the surface normal as displayed by Rhino, but it really uses the natural surface normal of the the surface according to UV direction, which may not be the same.

-Pascal